This application was submitted by investigators in the area of HIV-1 perinatal transmission research from Johns Hopkins University and Makerere University, to propose that an HPTN site be established at the current MU/Mulago Hospital HIVNET Perinatal site for the purpose of conducting HIV-1 perinatal and other intervention trials. Uganda is a developing African country with HIV-1 seroprevalence rates varying between 17-20 percent among the 20,000 women who deliver at Mulago Hospital in Kampala, Uganda each year. The clinical, data management, and laboratory resources necessary to screen, enroll, and retain HIV-1 infected mother-infant pairs in HIV-1 perinatal intervention trials will be derived from the current facilities, personnel, and organizational structure of the existing MU-JHU research collaboration. The investigators are experienced in conducting HIV-1 perinatal intervention trials in Uganda involving more than 1500 mother-infant pairs, including the HIVNET 006 Phase I/II nevirapine trial, the HIVNET 012 Phase IIB nevirapine/zidovudine trial, the UNAIDS Phase III PETRA trial, and the Phase I/II HIVIG trial. In addition, a pilot behavioral study of perceptions, attitudes, and opinions of community members on strategies for the interruption of vertical transmission is underway, in collaboration with the MU Department of Sociology and Social Sciences. Two HIVNET protocols are currently planned for this site: (1) the HIVNET 012 Phase III trial of the nevirapine 012 regimen versus extended nevirapine dosing for prevention of HIV transmission during breastfeeding, and (2) the HIVNET 027 Phase I/II study of the safety and immunogenicity of the ALVAC HIV vaccine in infants born to HIV-infected Ugandan women. Future expansion at this site is possible in addition to the current perinatal, vaccine, and behavioral trials. Expansion is anticipated with participation in behavioral, microbicide, or sexually transmitted disease protocols, in collaboration with other working groups within the HIV Prevention Trials Network.